Finger operated electro-optical lock and method

ABSTRACT

A finger operated electro-optical lock system in which an optical keyboard having at least one zone indicated thereon is illuminated by ambient energy until touched by a finger of the human hand blocking the radiant energy passing through the zone. A counter is thus enabled to cycle a numeric display. When the first digit of the combination appears in the display, the finger is lifted and reapplied until the second digit of the combination is displayed. The process is repeated until each digit of the combination has been displayed.

United States Patent Clark, Jr.

[ May 27, 1975 FINGER OPERATED ELECTRO-OPTICAL LOCK AND METHOD CharlesT. Clark, Jr., 2339 NE. 26th St., Lighthouse Point, Fla. 33064 Filed:Oct. 29, 1973 Appl. No.: 410,397

Inventor:

US. Cl. 70/278; 70/DIG. 51; 250/221;

317/124; 317/134 Int. Cl. E05b 49/00 Field of Search 70/278, DIG. 51;250/209,

References Cited UNITED STATES PATENTS 6/1973 Sharp ..250/83.3 uv 8/1973l-lanchett ..317/134 Clark 250/341 SWITCH OSCILLATOR 3,812,403 5/1974Gartner 317/134 Primary ExaminerAlbert G. Craig, Jr.

Attorney, Agent, or FirmBurns, Doane, Swecker & Mathis [57] ABSTRACT Afinger operated electro-optical lock system in which an optical keyboardhaving at least one zone indicated thereon is illuminated by ambientenergy until touched by a finger of the human hand blocking the radiantenergy passing through the zone. A counter is thus enabled to cycle anumeric display. When the first digit of the combination appears in thedisplay, the finger is lifted and reapplied until the second digit ofthe combination is displayed. The process is repeated until each digitof the combination has been displayed.

10 Claims, 4 Drawing Figures COUNTER DECODER FATENTEB HAY 2 7 ms Jyv OHLOSCILLATOR PATENTEUMYQ? sllllllllllllllllllllllllllllllllllllllllllllllllll mmaoowo 203 m mwooowoEwE x Q N mmooowa 21W mwZmo m N $52300 mo omo LEE? [I I 1 NR FINGEROPERATED ELECTRO-OPTICAL LOCK AND METHOD BACKGROUND OF THE INVENTION Thepresent invention relates to an optical keying system and moreparticularly to an electro-optical system for operating a lockingmechanism from a point externally of a building to which entry isdesired.

Electronic combination locking systems in which a series of switches areset in a predetermined combination in order to release a lockingmechanism are well known. The combination indicating devices for thesesytstems are generally mechanically actuated switches which are subjectto mechanical wear. Moreover. many of the electronic locking systemsoperate on the principle of selecting a predetermined combination bysimultancously positioning switches corresponding to the predeterminedcombination. These systems have the disadvantage that the requirement ofsimultaneous actuation or setting of the switches to the predeterminedcombination may offer an observer a view of the combination before it ispossible to move the switches away from their combination indicatingpositions.

The use of electromagnetic and optical scanners to read a card or otherkey" inserted into a slot is generally known and may be found, forexample, in the operation of parking lot closures. All systems of thistype suffer from the disadvantage that the slot into which the key mustbe placed may be obstructed by leaves, twigs. dirt andthe like bychildren and by vandals. In addition, the combination' of such systemshave not been readily modifiable.

It is accordingly an object of the present invention to obtain thedeficiency of these known systems and to provide a novel and improvedelectro-optical locking system and method in which a single optical keyis actu ated for predetermined periods of time for operating a lockingmechanism.

It is another object of this invention to provide a novel system andmethod in which the combination" of the mechanism may be easily andquickly manually modified.

It is yet another object of the invention to provide a novel circuit andmethod for evaluating a predetermined sequence of optically controlledtime intervals.

It is yet another object of the present invention to provide a novelsystem and method for operating a lock in which all of the operableparts thereof are located internally of the structure into which entryis desired.

It is still another object of the present invention to provide a noveloptical keyboard actuated by the presence of the human finger at apreselected zone on the board for predetermined time intervals.

These and many other objects and advantages of the present inventionwill be readily apparent to one skilled in the art to which theinvention pertains from the claims and from the perusal of the followingdetailed description in connection with the appended drawings.

THE DRAWINGS FIG. I is a functional block diagram of the system of thepresent invention;

FIG. 2 is a pictorial view in elevation of the optical keyboard of thesystem of FIG. I:

FIG. 3 is a section taken through the optical keyboard of FIG. 2: and.

FIG. 4 is a schematic circuit diagram of the logic circuit of FIG. 1.

THE DETAILED DESCRIPTION With reference now to FIG. 1 where the systemof the present invention is displayed in block diagram form, a switch 10is manually operated to enable or to unblock an oscillator 12 which inturn applies pulses to a counter 14. The number of pulses applied to thecounter may be decoded in a decoder 16 and displayed in a display 18.

The switch 10 may be of any suitable conventional type but desirably isof the type hereinafter illustrated and described in detail. Theoscillator 12 may be of the type illustrated in the circuit of FIG. 4but may also comprise any suitable conventional pulse generatingcircuit. It is desirable, but not necessary, that the pulses provided bythe oscillator 12 be of a uniform pulse repetition rate. The counter 14which receives the pulses from the oscillator 12 may be of any suitableconventional type such as a ring counter to continually increment inresponse to pulse application. Thus, the operation of the switch 10enables the oscillator 12 to cycle the counter 14 and to increment thedigit displayed by the display 18.

The operation of the switch 10 may also enable a timing circuit whichresets the counter 14 and enables the driver decoder circuit 16. In thismanner, the operation of the switch 10 may effect the initial reset ofthe counter 14 and enable the driver decoder circuit 16 so that thenumber of pulses provided by the oscillator 12 subsequent to theoperation of the switch 10 will be indicated to the switch operator atthe display 18. The display 18 will thus continually cycle until theswitch 10 is disabled at which time the oscillator 12 will cease toincrement the counter 14 and the last pulse digit indication will remainin the display 18. The timing circuit 26 may be operative after apredetermined time delay such as ten seconds to reset the counter 14 anddisable the drive decoder circuit 16 to remove the digit indication fromthe display 18.

With continued reference to FIG. I, the driver decoder circuit mayprovide input signals to a decoder circuit 20. These input signals will,of course,. reflect the digit indicated at the display 18. The decoder20 may be operative to transform the binary coded decimal contents ofthe counter 14 to decimal form. The disabling of the switch 10 may,through the timing circuit 26, effect the reading of the digit storedwithin the decoder 20 into a logic circuit 22 for evaluation purposes.

The operation of the logic circuit 22 in response to a selectedcombination is hereinafter discussed in greater detail in connectionwith FIG. 4. In the embodiment illustrated, the three digits of thecombination are the numerals 1, 7 and 9 and appropriate output terminalsfrom the decoder 20 are connected to the logic circuit 22. The remainingoutput terminals 0, 2-6 and 8 are desirably connected together and tothe logic circuit 22. The logic circuit 22 is thus operative to effectresetting of the circuit upon receipt of a single digit signal not inthe predetermined combination. In addition, the logic circuit 22 may beoperative to reset the circuit in the event that the digit signals arenot received in the appropriate predetermined sequence. The sequentialreceipt of the digits I, 7 and 9 in the desired order by the logiccircuit 22 will effect the operation of the lock 24 for a predeterminedtime interval as determined by the timing circuit 26 earlier described.

The operation of the embodiment illustrated in the figures will nowbriefly be announced. Th'e'individual desiring access to the interior ofan enclosure such as an apartment house or the like will approach thelocking mechanism from the exterior of the building and operate theswitch 10 by placing a finger over an indicated zone in a plate glasswindow. The placing of the finger over the appropriate zone will reducethe ambient light at that particular zone which will reset the counter14 through the timing circuit 26 to enable or unblock the oscillator 12to continually increment the counter 14 until such time as the finger isremoved from the switch.

With the finger against the glass, the counter will continuously cyclethe numeral indicated on the display 18 from to 9. The display 18 shouldbe located for ready viewing by the operator so that the operator mayremove his finger from the glass when the desired digit is displayed,i.e., the first digit of the combination. Removal of the finger tofreeze" the digit indicated on the display 18 will enable the decoder 20to provide an outputsignal on one of the 0 to 9 output terminals.

Should the first decoded digit be 0, 2-6 or 8 for the exemplary l, 7, 9combination illustrated, the logic circuit 22 will immediately reset.Should the first decoded digit be the digit 7 or 9, the logic circuit 22will also reset. Should the first decoded digit be the digit 1, i.e.,the first digit of the combination, the logic circuit 22 will internallyprepare for receipt of the next digit of the combination, i.e., thedigit 7.

If the operator does not again place his finger on the glass to effectoperation of the switch 10 within a predetermined time interval, e.g.,ten seconds. the timing circuit 26 will reset the logic circuit 22.Should the operator again effect operation of the switch 10, the counter14 will be reset and again cycle the display 18 until the operatorrecognizes the second digit of the combination and removes his fingerfrom the glass to freeze the display. If the second digit decoded isother than the second digit of the combination. the logic circuit 22will reset. If, however, the second decoded digit is the second digit ofthe combination, the logic circuit 22 will be internally enabled toreceive the third digit of the combination. The subsequent receipt ofthe third digit will effect operation of the lock 24 for a predeterminedtime interval sufficient to permit entrance into the enclosure.

The circuit may be provided with feedback from the locking mechanism todisable the display 18 so that the last digit of the combination cannotbe observed by an unauthorized person. Also, the display 18 may bedesirably shielded to prevent observation of the display during theoperation of the mechanism.

The physical relationship of the switch 10 may be as illustrated inFIGS. 2 and 3. With reference now to FIGS. 2 and 3, an opening 28 may beprovided from the inside of an external wall and the opening covered bya one-quarter inch thick sheet 30 of plate glass or other radiant energytransparent material having the desired structural characteristics. Anysuitable conventional means such as a metallic plate 32 and a pluralityof threaded fasteners 34 may be utilized to mount the sheet 30 over theopening 28. Thus. a convenient window is provided against which thefinger of the operators hand may be positioned.

As indicated in FIGS. 2 and 3, two zones 38 and 40 may be provided inthe window by the positioning of detectors 42 and 44. As indicatedschematically in FIG. 3, a suitable shield or baffle 46 may be providedto optically isolate the detectors 42 and 44 from radiation passingthrough all but the particular zone 38 or 40 with which it isassociated. Thus, the presence of a finger 36 at one of the zones in thewindow will optically block the radiant energy normally incident thereonand provide an output signal from the switch as will be subsequentlyexplained in greater detail in connection with the circuit of FIG. 4.

With reference now to FIG. 4, the switch 10 of FIG. 1 may include a PNPtransistor 01 connected between a 5-volt source of positive potentialand ground potential by an emitter resistor 50 and a collector resistor52. The bias for the base electrode for the transistor 01 may beprovided by any suitable conventional radiant energy responsive devices54 and 56 located respectively in the base-to-emitter andbase-to-collector circuits of the transistor Q1. The output signal fromthe transistor Q1 may be taken from the collector electrode thereof andpassed through a resistor 58 and the parallel combination of a resistor60 with a pair of serially connected converters 62 and 64 as the outputsignal from the switch 10.

The output signal from the switch 10 may be. as shown in FIG. 1, appliedto an oscillator circuit 12, a timing circuit 26 and a logic circuit 22.The oscillator circuit l2 may comprise a diode 66 in series with aparallel circuit in which a capacitor 68 is provided in one branchthereof and in which the other branch thereof includes an inverter 70 inseries with the parallel combination of an inverter 72 and a variableresistor 74. The output signal from the oscillator circuit 12 may bepassed through a capacitor 76 to the input terminal of a suitableconventional decade counter 14. The decade counter 14 may be providedwith parallel output terminals representing the binary digits 1, 2, 4and 8 and these output terminals may be connected to input terminals ofa driver decoder circuit 20 which. when enabled, may apply binary codedsignals to a suitable conventional display circuit 18 such as analphanumeric electronic tube. The output signals from the driver decodercircuit 20 may also be applied to the input terminals of a binary codeddecimal to decimal decoder 78 of the logic circuit 22.

With continued reference to FIG. 4, the output signal from the switch 10may also be provided to the timing circuit 22 which may include theseries connection of a resistor 80, diodes 82 and 84 and a resistor 86and the series connection of a resistor 88 and a pair of inverters 90and 92 in parallel therewith. The interconnection of the diodes 82 and84 may be directly connected to the interconnection of the resistor 88and the inverter 90 and isolated from ground potential by way of acapacitor 94. The output signal from the inverter 92 may be used as theRESET signal applied to the decade counter 14 and the output signal fromthe diode 90 may be utilized as the BLANK signal for application to thedriver decoder circuit 20 and one input terminal 94 of a NAND gate 96.

The logic circuit 22 of FIG. 4 may include a plurality of NAND gates 98.I00, I02 and 104. each connected to receive on one input terminalthereof the output signal from the switch circuit 10. Each of the NANDgates 100. I02 and I04 receives an input signal from a predetermined oneof the decimal output terminals of the binary coded decimal to decimaldecoder 78. In the preferred embodiment illustrated, the combination isa 3- digit combination with the 1 output terminal of the decoder 78connected to the other input terminal of the NAND gate 100, the 7"output terminal connected to the other input terminal of the NAND gate102 and with the 9 output terminal connected to the other input terminalof the NAND gate 104.

Any suitable conventional means may be used to effect the selectedconnection of NAND gate 100, 102 and 104 to the selected outputterminals of the decoder 78 to thereby establish the desiredcombination. Similarly, the connection of each of the noncombinationdigit output terminals of the decoder 78 to the NAND gate 98 may beeffected by any suitable conventional means.

The output signal from the NAND gate 100 may be applied to a timingcircuit 106 to enable a NAND gate 108 for a predetermined time interval.Similarly, the output signal from the NAND gate 102 may be applied tothe timing circuit 110 to enable a NAND gate 112 and the output signalfrom the NAND gate 104 applied through a timing circuit 114 to provide asignal at the other input terminal 116 of the NAND gate 96. The outputsignal from the NAND gate 96 may be connected to the relay coil 118 of aswitch within the lock 24.

In operation, the placing of a finger to block the ambient light to thedetector 42 of FIG. 3 may effect the unbalancing of the bias of thetransistor Q1 to drive the transistor into cutoff. The output signalfrom the collector electrode of the transistor Q] will assume a lowsignal level and the circuit including the invertors 62 and 64 operateas a Schmitt trigger to remove the normally high signal level signalfrom the oscillator 12, the timing circuit 26 and the decoder and logiccircuit 22.

Removal of the signal from the timing circuit 26 will effect thegeneration of the RESET signal applied to the decade counter 14 toeffect the resetting thereof and will also remove the normally highsignal level BLANK signal from the driver decoder 16 so that the decoder16 will be operative to drive the display 18 to visually indicate thedigit in the counter 14. Removal of the BLANK signal will also enablethe NAND gate 96 of the decoder and logic circuit 22.

The removal of the input signal from the oscillator 12 will effect theapplication of periodic pulses to the decade counter 14 through thecapacitor 76. The incrementing of the decade counter 14 will provide thesignals necessary to operate the display 18 through the driver decoder16.

When the finger is removed from the position illustrated in FIG. 3, thetransistor Q1 again saturates to disable the oscillator 12. Because ofthe time constants of the resistor 88 and capacitor 94, the resettingand blanking functions do not recur for a predetermined time interval,e.g., 10 seconds. If the switch 10 is again activated within thispredetermined time interval, the oscillator 12 again increments thecounter 14 to cycle the display 18 until such time as the finger of theoperator is again removed to disable the switch 10. This process isrepeated until the operator sequentially freezes by the removal of hisfinger at an appropriate time, each digit of the combination on thedisplay 18.

The removal of the finger to freeze" the digit displayed enables each ofthe NAND gates 98, 100, 102

and 104 of the decoder and logic circuit 22. Should the decoder 78provide a low signal level signal on any of the output terminals 0 2-6or 8, the NAND gate 98 will be disabled to disable the NAND gate 96 andthus the operation of the lock 24. Should the decoder 78 provide theNAND gate 100 with an appropriate low signal level signal during thistime, the NAND gate 100 will enable the NAND gate 108 so that the NANDgate 96 will remain in an enabled condition. Should the decoder 78provide a 7" output signal during this first sampling of the decoder 78,the NAND gate 102 will inhibit the NAND gate 108 and thus the NAND gate96 and the operation of the lock 24. Similarly, the presence of a 9output signal from the decoder 78 during this first sampling intervalwill inhibit the NAND gate 96 through the operation of the NAND gate104.

At the time of the next sampling interval, e.g., when the finger isagain removed to freeze the second digit of the combination in thedisplay 18, the NAND gate 102 will operate to enable the NAND gate 112and maintain the NAND gate 96 in an enabled condition. The subsequentreceipt of a 9 signal from the decoder 78 by the NAND gate 104 willeffect the operation of the NAND gate 96 to operate the relay 118associated with the lock 24.

ADVANTAGES AND SCOPE OF THE INVENTION Many of the advantages of thepresent invention will be readily apparent from the foregoingdescription of a preferred embodiment. For example, the optical keyboardof the present invention utilizes ambient radiation easily blocked bythe human'finger.

Another of the major advantages of the present system is thatobservation of the time intervals in which the finger is placed inproximity to the zone of the keyboard is easily hindered to protect thecombination of the lock. Further, the difficulty in measuring timeintervals is advantageous. The display of but a'single digitat one timeand an automatic reset feature precludes any residual indication of thecombination as may exist where the combination is set by a plurality ofswitches or the like.

Because of the resetting of the logic circuit upon the detection of asingle out-of-sequence time interval, security is assured. It will befurther appreciated that the combination cannot be detected by a senseof feel or mechanical noise since no mechanical combination locking orunlocking apparatus is utilized.

Moreover, the ease with which the combination may be changed facilitatesrevision of the security measures and thus reduces the likelihood ofcompromise. Since the device is finger operated, there are no keys to belost or stolen. 7

Another of the major advantages of thepresent invention is the completelack of moving parts in the operation of the system. The use of plateglass provides the desired structural strength and obviates thenecessity for an opening which may be obstructed by children or vandals.

The present invention may thus be embodied in other specific formswithout departing from the spirit or essential characteristics thereof.The presently disclosed embodiments are therefore to be considered inall respects as illustrative and not as restrictive, the scope of theinvention being indicated by the appended claims rather than by theforegoing description, and all changes which come within the meaning andrange of equivalancy of the claims are therefore intended to be embracedtherein.

What is claimed is:

l. A lock system for an enclosure entrance comprising:

manually operable electro-optical switch means internal of theenclosure;

pulse means responsive to said switch means for providing a series ofpulses at a predetermined repetition rate;

display means for providing a visual indicia internal of the enclosurerelated to the number of pulses provided by said pulse means, saiddisplay means being positioned for viewing by the operator of saidswitch means external of the enclosure so that the operation of saidswitch means may be selectively terminated to effect the display ofpredetermined visual indicia by said display means to the operatorexternal of the enclosure;

lock means; and,

circuit means internal of the enclosure and responsive to the effectingof the display of predetermined visual indicia by said pulse means foreffecting the operation of said lock means.

2. The system of claim 1 wherein said manually operable switch meansincludes:

a sheet of radiant energy pervious material;

a pair of detectors on the side of said sheet internal of the enclosure,each of said pair of detectors being responsive to ambient radiantenergy passing through a predetermined zone on said sheet from the otherside thereof; and,

circuit means responsive to an imbalance in the ambient radiant energydetected by said pair of detectors for effecting the operation of saidswitch means.

3. The system of claim 2 wherein said circuit means includes means forinhibiting the operation of said lock means in the event that the visualindicia display effected by said pulse means is other than predeterminedindicia.

4. The system of claim 1 wherein said circuit means includes means forinhibiting the operation of said lock means in the event that the visualindicia display effected by said pulse means is other than predeterminedindicia.

5. An electro-optical locking system for an enclosure entrancecomprising:

a sheet of radiant energy pervious material carried by the enclosure andproviding structural integrity for the enclosure;

a pair of detectors on the side of said sheet internal of the enclosure,each of said pair of detectors being responsive to radiant energy passedthrough a predetermined zone on said sheet;

a lock; and,

means internal of the enclosure responsive to a predetermined sequenceof the durations of a plurality of time intervals each related to animbalance in the radiant energy detected by said pair of detectors foreffecting the operation of said lock. said lock operating meansincluding: switch means for establishing a desired sequence of timeinterval duration, counter means advanced in response to each imbalancein the radiant energy detected by said pair of detectors to a valuerelated to the duration of the imbalance, and

circuit means for effecting the operation of said lock for apredetermined time interval in response to the sequential advancement ofsaid counter means to each of a predetermined plurality of values, saidcircuit means being reset in response to the termination of advance at avalue other than said predetermined plurality of values and in responseto the termination of advance at one of said predetermined plurality ofvalues in other than a predetermined sequence.

6. A system for operating the lock of an enclosure entrance comprising:

a sheet of radiation transparent material carried by the enclosure andproviding structural integrity for the enclosure;

a plurality of radiation responsive elements on the side of said sheetinternal of the enclosure, each of said elements being associated with apredetermined zone of said sheet;

switch means on the side of said sheet internal of the enclosureoperable in response to a modification of the radiation of said elementsfrom the side of said sheet external of said enclosure;

display means;

means responsive to the duration of the operation of said switch meansfor modifying the indicia displayed by said display means and forproviding a unique signal related to the duration of the operation ofsaid switch means responsively to the termination of the operation ofsaid switch means; and,

means for evaluating said unique signal and for effecting the operationof the enclosure lock in response to a favorable evaluation.

7. The system of claim 6 wherein said switch means is operable from aposition external of the enclosure by the positioning of the finger of ahuman hand in a predetermined position on said sheet of radiationtransparent material.

8. The system of claim 7 wherein said lock operating means includes:

switch means for establishing a desired sequence unique signalprovision.

9. The system of claim 8 wherein said sheet of material is glass havinga thickness of at least about onequarter inch.

10. A method for operating the locking device of the entrance to anenclosure without compromising the integrity of the enclosure comprisingthe steps of:

a. sequentially modifying for a plurality of time intervals the passageof radiant energy from a source external of the enclosure through apredetermined zone of a sheet of structural material opticallytransparent to the radiant energy;

b. detecting internally of the enclosure the duration of each of thetime intervals during which the passage of radiant energy is modified;

0. evaluating the sequence of time interval duration detection withrespect to a predetermined sequence; and,

d. operating the locking device responsively to the evaluation of thetime interval duration sequence evaluation.

1. A lock system for an enclosure entrance comprising: manually operableelectro-optical switch means internal of the enclosure; pulse meansresponsive to said switch means for providing a series of pulses at apredetermined repetition rate; display means for providing a visualindicia internal of the enclosure related to the number of pulsesprovided by said pulse means, said display means being positioned forviewing by the operator of said switch means external of the enclosureso that the operation of said switch means may be selectively terminatedto effect the display of predetermined visual indicia by said displaymeans to the operator external of the enclosure; lock means; and,circuit means internal of the enclosure and responsive to the effectingof the display of predetermined visual indicia by said pulse means foreffecting the operation of said lock means.
 2. The system of claim 1wherein said manually operable switch means includes: a sheet of radiantenergy pervious material; a pair of detectors on the side of said sheetinternal of the enclosure, each of said pair of detectors beingresponsive to ambient radiant energy passing through a predeterminedzone on said sheet from the other side thereof; and, circuit meansresponsive to an imbalance in the ambient radiant energy detected bysaid pair of detectors for effecting the operation of said switch means.3. The system of claim 2 wherein said circuit means includes means forinhibiting the operation of said lock means in the event that the visualindicia display effected by said pulse means is other than predeterminedindicia.
 4. The system of claim 1 wherein said circuit means includesmeans for inhibiting the operation of said lock means in the event thatthe visual indicia display effected by said pulse means is other thanpredetermined indicia.
 5. An electro-optical locking system for anenclosure entrance comprising: a sheet of radiant energy perviousmaterial carried by the enclosure and providing structural integrity forthe enclosure; a pair of detectors on the side of said sheet internal Ofthe enclosure, each of said pair of detectors being responsive toradiant energy passed through a predetermined zone on said sheet; alock; and, means internal of the enclosure responsive to a predeterminedsequence of the durations of a plurality of time intervals each relatedto an imbalance in the radiant energy detected by said pair of detectorsfor effecting the operation of said lock, said lock operating meansincluding: switch means for establishing a desired sequence of timeinterval duration, counter means advanced in response to each imbalancein the radiant energy detected by said pair of detectors to a valuerelated to the duration of the imbalance, and circuit means foreffecting the operation of said lock for a predetermined time intervalin response to the sequential advancement of said counter means to eachof a predetermined plurality of values, said circuit means being resetin response to the termination of advance at a value other than saidpredetermined plurality of values and in response to the termination ofadvance at one of said predetermined plurality of values in other than apredetermined sequence.
 6. A system for operating the lock of anenclosure entrance comprising: a sheet of radiation transparent materialcarried by the enclosure and providing structural integrity for theenclosure; a plurality of radiation responsive elements on the side ofsaid sheet internal of the enclosure, each of said elements beingassociated with a predetermined zone of said sheet; switch means on theside of said sheet internal of the enclosure operable in response to amodification of the radiation of said elements from the side of saidsheet external of said enclosure; display means; means responsive to theduration of the operation of said switch means for modifying the indiciadisplayed by said display means and for providing a unique signalrelated to the duration of the operation of said switch meansresponsively to the termination of the operation of said switch means;and, means for evaluating said unique signal and for effecting theoperation of the enclosure lock in response to a favorable evaluation.7. The system of claim 6 wherein said switch means is operable from aposition external of the enclosure by the positioning of the finger of ahuman hand in a predetermined position on said sheet of radiationtransparent material.
 8. The system of claim 7 wherein said lockoperating means includes: switch means for establishing a desiredsequence unique signal provision.
 9. The system of claim 8 wherein saidsheet of material is glass having a thickness of at least aboutone-quarter inch.
 10. A method for operating the locking device of theentrance to an enclosure without compromising the integrity of theenclosure comprising the steps of: a. sequentially modifying for aplurality of time intervals the passage of radiant energy from a sourceexternal of the enclosure through a predetermined zone of a sheet ofstructural material optically transparent to the radiant energy; b.detecting internally of the enclosure the duration of each of the timeintervals during which the passage of radiant energy is modified; c.evaluating the sequence of time interval duration detection with respectto a predetermined sequence; and, d. operating the locking deviceresponsively to the evaluation of the time interval duration sequenceevaluation.